Histamine Phosphate
307.141H-Imidazole-4-ethanamine, phosphate (1:2).
Histamine phosphate (1:2)
[51-74-1].» Histamine Phosphate contains not less than 98.0 percent and not more than 101.0 percent of C5H9N3·2H3PO4, calculated on the dried basis.
Packaging and storage—
Preserve in tight, light-resistant containers.
Identification—
A:
Dissolve 0.10 g in a mixture of 7 mL of water and 3 mL of 1 N sodium hydroxide, and add the solution to a mixture of 50 mg of sulfanilic acid, 10 mL of water, 2 drops of hydrochloric acid, and 2 drops of sodium nitrite solution (1 in 10): a deep red color is produced.
B:
Dissolve 50 mg in 5 mL of hot water, add a hot solution of 50 mg of picrolonic acid in 10 mL of alcohol, and allow to crystallize. Filter the crystals with suction, wash with a small amount of ice-cold water, and dry at 105
for 1 hour: the crystals so obtained melt between 250 and 254, with decomposition.
for 1 hour: the crystals so obtained melt between 250 and 254, with decomposition.
C:
A solution (1 in 10) responds to the tests for Phosphate 
191
.
191.
Loss on drying 731—
Dry it at 105 for 2 hours: it loses not more than 3.0% of its weight.
731—
Dry it at 105 for 2 hours: it loses not more than 3.0% of its weight.
Assay—
Dissolve about 150 mg, accurately weighed, of Histamine Phosphate in 10 mL of water. Add 5 mL of chloroform and 25 mL of alcohol, then add 10 drops of thymolphthalein TS, and titrate with 0.2 N sodium hydroxide VS. Each mL of 0.2 N sodium hydroxide is equivalent to 15.36 mg of C5H9N3·2H3PO4.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
| Monograph | Elena Gonikberg, Ph.D.
Senior Scientist 1-301-816-8251 |
(MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine |
USP32–NF27 Page 2557
Pharmacopeial Forum: Volume No. 29(5) Page 1504